Considering the development of biota in relation to changing abiotic factors shows
that long intervals without sharp environmental changes, under transgression, active
hydrodynamics, and a diversity of ecological niches, favor increases in the biodiversity of
organisms. The reduction of biota is caused by quick changes in conditions, especially by
multiple alternations of opposite trends (transgression – regression, warming – cooling,
etc.). Moreover, negative effects arise from events expressly adverse for the development
of organisms, such as the global development of anoxia in the oceans, powerful outflow
of trap basalts and volcanism, and collisions of the Earth with cosmic bodies. The effects
of various factors are identified especially vividly during biotic crises.
Abiotic factors of the development of biota are predetermined by three fundamental
causes – terrestrial (tectonics, volcanism), orbital, and cosmic. In many cases, these
causes and factors predetermined by them operated simultaneously or were closely
spaced on the geologic timeline. Since the cause-effect relation between them is
definitely absent, we may assume that large-scale changes in the Earth's natural
environment are caused by more general cosmic factors that are outside the limits of the
solar system.
